#include <stdio.h>
int main()
{
    int max4(int a, int b, int c, int d);
    int a, b, c, d, max;
    printf("Please enter 4 interger numbers:");
    scanf("%d %d %d %d", &a, &b, &c, &d);
    max=max4(a, b, c, d);
    printf("max=%d\n", max);
    return 0;
}
int max4(int a, int b, int c, int d)
{
    int max2(int a, int b);
    int m;
    m = max2(a, b);
    m = max2(m, c);
    m = max2(m, d);
    return m;
}
int max2(int a, int b)
{
    if (a > b)
        return a;
    else
        return b;
}